A mobile communication system has been developed to provide a voice service, while ensuring the user's activity. However, the mobile communication system has expanded a scope to a data service, as well as the voice service, and currently, explosive increase in traffic has caused shortage of resource and, as users request higher speed services, a more advanced mobile communication system is required.
The requirements of a next generation mobile communication system are required to support acceptance of explosive data traffic, a significant increase in a data rate per user, acceptance of a significantly increased number of connected devices, very low end-to-end latency, and high energy efficiency. To this end, various technologies such as dual-connectivity, massive multiple input multiple output (MIMO), in-band full duplex, non-orthogonal multiple access (NOMA), support of super-wideband, device networking, and the like, have been researched.
In the current LTE(-A) system, only CSI-RS patterns (or CSI-RS resources) for 1, 2, 4, or 8 ports exist and all have a form of power of 2.
However, in case where the number of antennas is large in a transmitter (or a transmitting device) like a massive MIMO system, the CSI-RS pattern may have various forms, and an antennas configuration may be different even for the same number of antennas.
Considering the structure of the transmitting antenna having various sizes and various patterns, it may be inefficient to limit the number of CSI-RS ports to only the power of 2.